Alloy



ther characterized by increased tensile strength Patented May 7, 1935UNITED STATES PATENT OFFICE ALLOY No Drawing? Application September 20,1933, Serial No.'690,293

5 Claims.

The invention relates to magnesium-base alloys and is directed to thedevelopment of alloys oi. this class which, while possessing thedesirable characteristics of the class as a whole, are furmany of thestrong aluminum alloys. It is quite generally appreciated that anyimprovement in magnesium alloys which means increased yield point,strength and elongation will be very valuable, and for this reasoneiiorts have been continuously expended in the search for improvementalong these lines. It is to this general ob- -ject that the presentinvention is directed.

A particular object of the invention is the modification ofmagnesium-base alloys containing tin, manganese and aluminum by theaddition of at least one of the metals of the class comprising zinc andcadmium to produce an alloy of increased tensile strength, yield point,elongation, and corrosion resistance.

I have discovered a very useful range of composition over which aluminumadditions are particularly effective in producing the desiredimprovement in tensile properties without serious detriment to the otherproperties of this class of alloys. According to my invention the alloysmay contain from 0.1 to 12.0 per cent tin, from 0.5 to 10 per cent ofaluminum and from 0.1 to 1.0 per cent of manganese. Alloys of thisgeneral nature are disclosed and claimed in my copending application,Serial No. 643,033, filed November 17th, 1932, of which this presentapplication is a continuation-in-part. The aluminum increases thetensile strength as much as 15 per cent, the yield point as much as 20per cent and the elongation as much as 100 per cent. As a result of thetests which I have conducted I have found further that the magnesiumalloy containing tin, aluminum, and manganese is superior to amagnesium-base alloy containing only aluminum because of improved hotWorking characteristics, particularly, within the preferred range,hammer-forging characteristics, and, over the whole disclosed range,extrusion characteristics.

The improvement in physical properties is particularly marked throughoutwhat I consider to be the preferred range of composition, which includesalloys containing from 4.0 to 6.0 per cent of tin, 3.5 to 4.5 per centof aluminum, and 0.5 to 0.8 per cent of manganese.

When used for purposes suited to articles produced by extrusionprocesses, my improved alloys may contain at least one of the class ofmetals composed of zinc and cadmium. -In my alloy these elements aresubstantially equivalent with respect to their effect on the corrosionresistance of the alloy. Amounts of zinc or cadium between about 0.1 percent and 5.0 per cent materially improve. the corrosion resistance ofthe alloy without any undesirable effect on the physical properties.Improved alloys according to the scope of the present invention containfrom about 0.1 to 12.0 per cent of tin, from about 0.5 to 10.0 per centof aluminum, from about 0.1 to 1.0 per cent of manganese and at leastone of the class of metals composed of zinc and cadmium in total amountbetween about 0.1 per cent and 5.0 per cent, the balance beingsubstantially magnesium. As a preferred magnesium-base alloy within thisrange I use an alloy containing from about 4.0 per cent to about 6.0 percent of tin, from about 3.5 per cent to about 4.5 per cent of aluminum,from about 0.5 per cent to about 0.8 per cent of manganese and fromabout 1.0 per cent to about 3.0 per cent of at least one of the elementszinc or cadmium. If the alloys are to be forged orrolled, asdistinguished from extruded, they should preferably not contain overabout 1 per cent of zinc.

While the magnesium-base alloys containing tin, aluminum and manganese,and at least one of the class of elements cadmium and zinc, are entirelysatisfactory in achieving the objects and advantages hereinaboveenumerated, other elements may be added to produce a new property in thealloys or to aifect or modify an old property without substantiallydeparting from the invention so long as the material properties of thealloy are not substantially impaired.

The alloys herein disclosed and claimed may be subjected to the usualthermal treatments for the purpose of improving or altering theirproperties.

I claim:

1. An alloy containing from about 0.1 to about 12.0 per cent. of tin,from about 0.5 to about 10.0 per cent of aluminum, from about 0.1 toabout 1.0 per cent of manganese, and at least one of the class ofelements composed of zinc and cadmium in total amount betwen about 0.1per cent and 5.0 per cent, the balance being substantially magnesium.

2. An alloy containing from about 0.1 to 12.0

per cent of tin, from about 0.5 to 10.0 per cent of aluminum, from about0.1 to- 1.0 per cent of manganese and from about 0.1 to 5.0 per cent ofzinc, the balance being substantially magnesium.

3. An alloy containing from about 0.1 to 12.0 per cent of tin, fromabout 0.5 to 10.0 per cent of aluminum, from about 0.1 to 1.0 per centof manganese and from about 0.1 to 5.0 per cent of about 0.5 per cent toabout 0.8 per cent of manganese, and from about 1.0 per cent to about3.0

per cent total of at least one of the class of elements composed of zincand cadmium, the balance being substantially magnesium.

5. An alloy containing from about 0.1 per cent to about 12.0 per cent oftin, from about 0.5 per cent to about 10.0 per cent of aluminum, fromabout 0.1 per cent to about 1.0 per cent of manganese, and from about0.1 per cent to about 1.0 per cent of zinc, the balance beingsubstantially magnesium.

ROBERT T. WOOD.

